Field of the Invention
The invention relates in general to an electronic device, and more particularly to a head mounted display system.
Description of the Related Art
At present, the head mounted displays are mainly classified into two types. The first type is an immersive type head mounted display, also referred to as a non-see-through head mounted display. The significant feature of the immersive type head mounted display is to completely isolate the user from the external light so that the user is completely immersed into the environment provided by the head mounted display. The second type is a see-through type head mounted display, also referred to as an optical see-through head mounted display. The significant feature of the optical see-through head mounted display is not to isolate the external light from the user so that the user can see the outside world (real image) and the image (virtual image) provided by the head mounted display concurrently. In the summer sun, the brightness may reach 10,000 Lux, but the brightness may only 1 Lux in the shaded place. The real scene is 100 dB. However, the human eye's dynamic range is about 40 dB, so the human eyes cannot see the details of the dark portion and the bright portion in a short period of time concurrently. Because the conventional optical see-through head mounted display does not isolate the external light from the user, the user cannot see the details of the dark portion and the bright portion in the real scene concurrently with the aid of the conventional optical see-through head mounted display.